Hotpoint FFUQ fridge freezer 2013 Error A2. Freezer section not working

I will try and help with this problem...Hotpoint FFUQ Fridge Freezer 2013 

Freezer sensor fault

Issue: The compartment temperature in my Freezer is incorrect. You may have a blockage in The Matrix​ -  too much ice may build up​ or one of the sensors have failed add additional directing coolant to the freezer

Hotpoint FFUQ Fridge Freezer 2013